Make edb.server an (empty) Django app

-   Add Django dependency to requirements.txt
-   Add SQLite3 dependency to README.markdown
-   Run `syncdb` from bootstrap.py to set up dev database
Refactor client and server

-   Use salts instead of fixed indices to seed the stream cipher. This
    allows us to store non-sequential encrypted data and still decrypt.
    Downside: database size inflation of x2.

-   Encode encryptions as base64 rather than raw bytes. This will allow
    easier passing via JSON later.

-   Implement server functions on an abstract Django model,
    EncryptedModel. We expose a new manager function:

        model.objects.encrypted_filter(field=query)

    Queries can be generated by the new client `query()` function.

-   Use Django's unittest framework to run tests. This allows us to
    create a temporary database to run our tests against.

-   Add preliminary error handling to the client and server.
Merge pull request #2 from Pringley/feature/djangoserver

Refactor client and server